/Engine/Source/Runtime/Engine/Classes/EditorFramework/AssetImportData.h
Convert an absolute import path so that it's relative to either this object's package, BaseDir() or leave it absolute
static [FString](API\Runtime\Core\Containers\FString) SanitizeImportFilename ( const [FString](API\Runtime\Core\Containers\FString) & InPath, const [UPackage](API\Runtime\CoreUObject\UObject\UPackage) * Outermost )